How did a piece of ice cut through the solid steel hull of the Titanic?
In: Physics
I’m not a scientist but, If a wooden fencepost can damage a steel truck I imagine an iceberg can damage a steel ship
It didn’t, it tore and bent and popped rivets between the myriad of steel plates that made up the hull. At the scale of a million ton chunk of ice versus a much lighter ship this is akin to stabbing an aluminum can with a screwdriver.
TLDR: the high momentum of the titanic and high inertia of both the titanic and the iceberg meant the hull experienced pressures at the point of contact beyond its capabilities to withstand.
The titanic, and all boats, are essentially hollow shells of wood or metal so they can be buoyant and float.
When the titanic hit the iceberg, it had a lot of momentum (momentum = speed times mass, it wasn’t going very fast but was veeeeery heavy). High mass objects also have a lot of inertia. Inertia essentially describes how hard something is to de/accelerate, or more specifically, to decrease/increase its momentum. Since the titanic is so heavy, it has a lotttttt of inertia. The same goes for the iceberg.
When two objects collide, there must be a relative difference in speed (one is going faster than the other in at least one direction). In the case of the iceberg, it was more or less stationary relative to the titanic.
At the exact moment of impact, the titanics momentum wants to keep carrying it forward. However, the high inertia iceberg is now in the way. As soon as they make contact, the titanic begins decelerating, as its momentum is being transferred to the iceberg, which accelerates in response.
At the point of contact, the steel is experiencing insane force equivalent to the force accelerating the iceberg and decelerating the titanic. The contact area of the iceberg on the hull is very small. This results in incredibly high pressure on the steel since pressure = force / area, so high force in a small area results in high pressure (fun fact, its pressure not force that causes materials to fail although they are proportional)
Remember how I mentioned ships are largely hollow? All of this pressure is concentrated on a small patch of steel and behind it is empty air, so there is nothing to support the hull. So, either the hull material itself, or the joining materials (rivets, bolts, etc) would tear apart would rip apart under the stress. Consider the alternate case of a block of solid steel with similar mass and momentum to the titanic hitting the iceberg. It might wind up with some dents but wouldn’t tear apart.
So, there are a few options that can occur at the time of impact.
1: The titanic breaks the iceberg
2: The titanic bounces off the iceberg
3: The iceberg breaks the titanic
We wound up with the third option because of the reasons I listed above.
I doubt option two would happen unless we were dealing with something solid like the solid steel example I described above, and even then this would more likely break the iceberg giving us option one.
Ultimately we wound up with option three for the reasons above.
Ironically, if the impact pressure had been more evenly distributed on the hull, it might’ve survived (albeit with some damage). It might’ve still survived if the impact occurred in a location with steel girders behind it to help absorb and distribute the impact, although that’s more uncertain because it would also result in high internal stresses which could also have ripped the ship apart.
Is aluminum stronger than fingernails? Of course! But observe you can easily poke your fingernail through a sheet of aluminum foil.
Pretty much the same.
If a snowball can dent a car door if you throw it hard enough, imagine what a billion tons of ice can do to some riveted steel not much thicker.
What if the Titanic crashed into a giant, fluffy cotton ball that also weighed 1.5 million tons. Would the Titanic still have sunk?
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